A short form of the URLs to the products is needed in order to be able to create the URL automatically for QR codes in flyers, advertisements and print products in general. This URL should contain the product number. 
There are plugins for this, but they only support REST notation. 

Ideally, Shopware can do both in the core:

Standard RFC 3986
https://www.xxxx.de/?sku=12345678

REST notation
https://www.xxxx.de/12345678

The print production software InBetween requires the URL in the standard RFC 3986.

It allows external programmes to generate the appropriate links (URLs) to certain products and variants more easily. The "regular" links such as domain/category/article name/variant would be too long and also difficult to "guess" for an automatic generation of URLs.